Method of producing condensers or the like for heat exchange apparatus



Feb. 22, 1949. N. KRAMER METHOD OF PRODUCING CONDENSERS OR THE LIKE FOR HEAT EXCHANGE APPARATUS Filed Jan. 12, 1945 I N VEN TOR.

Patented Feb. 22, 1949 METHOD OF PRODUCING CONDENSERS OR THE LIKE FOR HEAT EXCHANGE APPA- RATUS Nathan Kramer, Trenton, N. J., assignor to Kramer Trenton Company, Trenton, N. J., a corporation of New Jersey Application January 12,1945, Serial No. 572,563

'1 This invention relates to a condenser, or the like, and method of producing the same, intended chiefly for use in refrigerating apparatus. Various ways of connecting and using such a condenser in refrigerating apparatus are well known to those skilled in the art and constitute no part of this invention which is directed to the construction of the condenser itself.

An object of the invention is to provide a construction in which the parts are so formed that the fiuid conducting tube, or tubes, and fins may be assembled into operative relationship without the necessity of attaching the return bends, or curved connecting portions, to the straightparallel runs of the tube following the location of the fins on the said parallel runs.

Another object is to provide a construction in which the conducting tube is formed in a continuous lengthwith appropriate bends, and thereaft-er assembled with its group of fins by a single relative movement of the tube and fins.

Another object is to provide a construction in which the conducting tube is formed in a continuous length with appropriate bends, its group of fins is arranged in proper alignment and spacing, and operative relationship between the tube and fins is accomplished by passing the tube through the fins in a single movement.

Another object is to provide the construction just described with fins that embrace and have thermal contact with substantially more than one-half the cross-sectional circumference of the tube.

Another object is to provide a construction in which the return bends, or curved connecting portions, of the tube are deformed from the crosssectional shape of the remainder of the tube in order to permit the operational assembly of the tube and fins as hereinabove described.

Another object is to provide a construction in which the return bends, or curved connectin portions, of the tube are flattened in the direction of the plane of the tube in order to permit the operational'assembly of the tube with fins that are shaped to embrace and have thermal contact with substantially more than one-half the crosssectional circumference of the tube.

Another object is to provide a construction in which the fins have openings therein each of which is fitted for the-passage therethrough of one return bend, or curved connecting portion, and two parallelruns of the tube.

Another object is to provide certain improvements in the form, construction, arrangement, and method of production whereby the above 2 Claims. (Cl. 29-1573) 2 named and other objects may effectively be attained. I

Practical embodiments of the invention are represented in the accompanying drawings, in

which Fig. 1 represents a detail, broken, partial side view of a fiuid conducting tube with its group of fins in operative position thereon;'

Fig. 2 represents an end view of the parts shown in Fig. 1;

Fig. 3 represents a vertical section taken in the plane of the line III-III of Fig. 1, looking in the direction of the arrows; i

Fig. 4 represents a horizontal section taken in the plane of the line IVIV of Fig. l, looking ln the direction of the arrows;

Fig. 5 represents a detail face view of a portion of one of the fins;

Fig. 6 represents a vertical section taken in the plane of the line VI-VI of Fig. 5, looking in the direction of the arrows.

Fig. 7 represents a horizontal section taken in the plane of the line VII-VII of Fig. 5, looking in the direction of the arrows;

Fig. 8 represents a detail face view of a portion of a modified form of fin;

Fig. 9 represents a vertical section taken in' the plane of the line IX'-IX of Fig. 8, looking in the direction of the arrows;

Fig. 10 represents a horizontal section taken in the plane of the line X--X of Fig. 8, looking in the direction of the arrows;

Fig. 11 represents a detail face view of a portion of a second modified form of fin; and

Fig. 12 represents a horizontal section taken in the plane of the line XII-XII of Fig. 11 looking in the direction of the arrows.

Referring to the form shown in Figs. 1 to '7 inclusive, the tube which forms a conduit for the fluid passing therethrough is of sinuous or serpentine form and includes a plurality of straight parallel runs I, with a plurality of return bends, or curved connecting portions 2, each of the latter serving to connect a'palr of runs. While the runs and bends have been separately named and marked they are, in the practiceof this invention, integral with each other, the tube as a whole being composed of a single length of suitable material such, for instance, as copper or brass, and bent into its sinuous shape by suitable means and method which are well known to those skilled in this art and need not be described.

Operatively associated with the tube or conduit I, 2, is a group of fins 3 which are preferably stamped or died from strips of appropriate material, such as copper or brass, the stamping operation serving to provide the fins with apertures of such size and contour as to provide for and facilitate the assembly of the fins with the tube. Each of said apertures includes a pair of substantially circular portions 4, 4 connected by an elongated portion 5; the portions 4 being of such size as to receive with a sliding fit the runs 1 .of the tube and being provided, in the stamping or dieing operation, with 'flanges or collars 6 that are fitted to rest against and in contact with the tube when the parts are in operative assembly.

Each return bend 2 at one side or edge of the tube is deformed intermediate the parallel runs I of the tube by being flattened in the direction of the plane of the tube as a whole, as clearly shown at 1 in Fig. 4, which deformation naturally results in increasing the cross-sectional axes of the return bends in the direction of the said plane of the tube and decreasing their transverse axes; said increase serving to compensate for said decrease so as to prevent any substantial restriction upon the passage of fluid through the tube. The said transverse axial dimension is slightly less than the width of the portions 5 of the apertures in the fins 3, with the result that the fins may be caused to assume their operative assembly with the tube, as shown in Fig. 1 by relative movment of the fins and tube. In accomplishing this assembly, a suitable number of fins are placed in a magazine, rack or comb, wherein they are held in predetermined spaced relationship with each other and with their apertures in alignment. The tube is then thrust endwise into the group or gang of fins until the return bends 2 at one end of the tube have passed entirely through the fins while the return bends at the other end of the tube remain protruding therefrom, as illustrated in Fig, 1. This relative motion of the tube and fins is preferably accomplished by moving the tube to the right in Fig. 1 so that the flanges 6 on the fins may readily be drawn over the parallel runs l of the tube in close thermal con-v tact therewith. This operational assembly of a tube and group or gang of fins is permitted by b and by the shape and size of the apertures 4,.

5 in the fins 3.

Owing to the fact that the width of the portions 5 of the apertures is considerably less than the diameter of the portions 4, the latter, together with their flanges 6, are permitted to embraceand be in snug thermal contact with substantially more than one-half (actually about three-quarters) the circumferential cross section of the run-s l of the tube, thereby insuring ade= quate and efficient radiation by the fins.

Following the assembly of the parts as just described, they may be united into fixed relationship'by any approved step or means such, for instance, as soldering accomplished by dipping the whole into a bath of liquid solder after suitable treatment of the flanges B and adjacent por- 1 tions of the tube to which they are to be soldered.

The-form and arrangement of the parts not :only pern its attainment of the advantages in inethod of construction and result hereinabove set =forth,- but an added desirable feature resides in thefact that the portion 5 of the apertures in the fins permits increased circulation of air through the structure as well as increased radiation, as comparedwith a similar structure in which portions 5, or comparable openings, do not exist. In other words, the shape of the apertures 4, 5, in the fins, in conjunction with the shape of the bends 2 of the tube, provides for a construction which is not only adapted to assembly by the simplest sort of procedure, but is also capable of wholly satisfactory thermal contact between the tube and fins, wholly satisfactory radiation. and wholly satisfactory air circulation.

, The modified form represented in Figs. 8, 9 and 10. is like the form shown in Figs. 1 to 7 inclusive, except that the fins, here marked 8, include two rows of apertures 4, 5 so that each fin may be associated with a pair of tubes or conduits I, 2. The apertures are preferably ar-- ranged in staggered relationship, as well shown in Fig. 8; and it may be added that the fins could be provided with more than two rows of apertures for association with more than two tubes. if desired.

The second modified form shown in Figs. 11 and 12 is like the form shown in Figs. 1 to 7 inclusive except that the portion of the fin apertures, here marked 9, which takes the place of the portion marked 5 in the form shown in Figs. 1 to 7. is somewhat narrower than the said portion 5 so as to increase the extent to which the portions corresponding to the portions 4, here marked I 0. embrace and have thermal contact with the tube.

In addition to the advantages hereinabove mentioned, it way be noted that the form or :hape of the apertures in the fins, whereby two ubstantally circular portions fitted to embrace runs of the tube are connected by an elongated portion, provides a certain resilience or elasticity to the fins so that they can have good thermal contact with the tube regardless of slight variaions in the diameter of the latter. In the manufacture of these tubes there is a small commercial tolerance with the result that appreciable variations are found in the outside diameter of the tube as purchased, and this has led to imperfect thermal contact between the tube and fins when the tube was undersize, or to difficulty in assembling the fins on the tube when the tube was oversize, because the apertures in the fins have heretofore been substantially inflexible in size. The present invention overcomes this previously existing difficulty, because the fin apertures can be made slightly undersize so as snugly to fit undersized tubes, while the resiliency of the fins at the apertures will permit ready assembly of the fins with oversized tubes.

In connection with all the forms, it may be said that the number of tubes and fins may be varied to suit the requirements of any contemplated installation or unit; that the extremities of a plurality of tubes may be joined together or to manifolds, or connected in any other appropriate way to permit circulation of the fluid therethrough; that the spacing of the parallel runs of the tube may be varied; that the spacing of the fins may be varied; and that the fins may be provided with spacing and/or aligning elements. All this is well within the knowledge and practice of this art, and is deemed to call for no more than the mere recital thereof. Furthermore. while the invention has been described as a condenser for refrigerating apparatus, it will.

be understood that the construction is adapted to use in other forms or kinds of heat transfer ing steps: providing a single piece tube bent sinuously in a single plane andhaving substantially straight parallel portions connected by curved portions; flattening certain of the curved portions in the direction of the plane of the tube; providing a plurality of flns having apertures corresponding in shape with the combined cross section of the straight and flattened curved portions of the tube; and moving the tube and flns with respect to each other to cause the flattened curved portions of the tube to pass through the said apertures and the flns to be seated on the said straight portions.

2. A method of producing an apparatus of the character described, which includes the following steps: providing a single piece tube bent sinuously in a single plane and having substan- 6 tially straight parallel portions connected by curved portions; flattening certain of the curved portions in the direction of the plane of the tube: providing a plurality of fins having apertures corresponding in shapewith the combined cross section of the straight and flattened curved portions of the tube; arranging the fins in a group with their said apertures in alinement; and moving the tube and fins with respect to each other to cause the flattened curved portions of the tube to pass through the said apertures and the fins to be seated on the said straight portions.

NATHAN KRAMER.

I REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,773,249 Yeager Aug. 19, 1930 1,788,068 Scott Jan. 6, 1931 1,789,591 McIntyre Jan. 20, 1931 2,092,170 Kritzer Sept. 7, 1937 2,181,107 Przyborowski Nov. 21, 1939 2,318,891 Sideil May 11, 1943 2,371,215

Bensen Mar. 13, 1945 

